Power circuit and mainboard with application of power circuit

Abstract

The invention relates to a power circuit and a mainboard with application of the power circuit. The power circuit comprises a processing chip, a power supply unit, a fan interface and a voltage conversion unit, wherein the voltage conversion unit comprises a first capacitor, a first end of the first capacitor is connected to the power supply unit and a detection pin of the fan interface, and a second end of the first capacitor is taken as an output end of the power circuit; when a control signal sent out by a detection pin of the processing chip has a high level, the power supply unit can provide a first voltage to the first capacitor; and when the control signal has a low level, the first end of the first capacitor is grounded, a second end of the first capacitor outputs a second voltage, and the absolute value of the second voltage is equal to the first voltage. According to the invention, the second voltage output by the power circuit can be provided to a serial-port management chip, so that communication between the mainboard and external serial-port equipment can be achieved by the serial-port management chip.

Description

technical field [0001] The invention relates to a power supply circuit and a mainboard using the power supply circuit. Background technique [0002] The serial port is a common communication interface on the computer, and because the serial port level is a negative logic level, it usually needs + / -12V voltage power supply, and the communication between the motherboard and the serial device is completed through a serial port management chip. At present, there are two power supply methods for computers, one is a standard ATX or BTX power supply for desktop computers, which outputs + / -3.3V, + / -5V, + / -12V and +5VStandby voltage; the other is for power supply The power adapter used by the notebook computer, but the power adapter can only provide positive voltages such as +12V, +24V to the motherboard, and cannot provide negative voltage for the serial port management chip to realize the communication between the motherboard, the serial port management chip and the serial device. ...

AI Technical Summary

Problems solved by technology

At present, there are two power supply methods for computers, one is a standard ATX or BTX power supply for desktop computers, which outputs + / -3.3V, + / -5V, + / -12V and +5VStandby voltage; the other is for power supply The power adapter used by the notebook computer, but the power adapter can only provide positive voltages such as +12V, +24V to the motherboard, and cannot provide negative voltage for the serial port management chip to realize the communication between the motherboard, the serial port management chip and the serial device

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